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-rw-r--r--arch/arm/Kconfig2
-rw-r--r--arch/arm/include/asm/assembler.h22
-rw-r--r--arch/arm/kernel/entry-armv.S4
-rw-r--r--arch/arm/kernel/head.S13
4 files changed, 32 insertions, 9 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index db524e75c4a..290a4b57617 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1229,7 +1229,7 @@ config SMP
config SMP_ON_UP
bool "Allow booting SMP kernel on uniprocessor systems (EXPERIMENTAL)"
depends on EXPERIMENTAL
- depends on SMP && !XIP && !THUMB2_KERNEL
+ depends on SMP && !XIP
default y
help
SMP kernels contain instructions which fail on non-SMP processors.
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index 749bb662240..72d3389e9c1 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -157,16 +157,24 @@
#ifdef CONFIG_SMP
#define ALT_SMP(instr...) \
9998: instr
+/*
+ * Note: if you get assembler errors from ALT_UP() when building with
+ * CONFIG_THUMB2_KERNEL, you almost certainly need to use
+ * ALT_SMP( W(instr) ... )
+ */
#define ALT_UP(instr...) \
.pushsection ".alt.smp.init", "a" ;\
.long 9998b ;\
- instr ;\
+9997: instr ;\
+ .if . - 9997b != 4 ;\
+ .error "ALT_UP() content must assemble to exactly 4 bytes";\
+ .endif ;\
.popsection
#define ALT_UP_B(label) \
.equ up_b_offset, label - 9998b ;\
.pushsection ".alt.smp.init", "a" ;\
.long 9998b ;\
- b . + up_b_offset ;\
+ W(b) . + up_b_offset ;\
.popsection
#else
#define ALT_SMP(instr...)
@@ -177,16 +185,24 @@
/*
* SMP data memory barrier
*/
- .macro smp_dmb
+ .macro smp_dmb mode
#ifdef CONFIG_SMP
#if __LINUX_ARM_ARCH__ >= 7
+ .ifeqs "\mode","arm"
ALT_SMP(dmb)
+ .else
+ ALT_SMP(W(dmb))
+ .endif
#elif __LINUX_ARM_ARCH__ == 6
ALT_SMP(mcr p15, 0, r0, c7, c10, 5) @ dmb
#else
#error Incompatible SMP platform
#endif
+ .ifeqs "\mode","arm"
ALT_UP(nop)
+ .else
+ ALT_UP(W(nop))
+ .endif
#endif
.endm
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 955cf5f539e..7f22a11a510 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -842,7 +842,7 @@ __kuser_helper_start:
*/
__kuser_memory_barrier: @ 0xffff0fa0
- smp_dmb
+ smp_dmb arm
usr_ret lr
.align 5
@@ -959,7 +959,7 @@ kuser_cmpxchg_fixup:
#else
- smp_dmb
+ smp_dmb arm
1: ldrex r3, [r2]
subs r3, r3, r0
strexeq r3, r1, [r2]
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index fd94e4e82fc..359e54e83bd 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -412,10 +412,17 @@ __fixup_smp_on_up:
add r4, r4, r3
add r5, r5, r3
2: cmp r4, r5
+ movhs pc, lr
ldmia r4!, {r0, r6}
- strlo r6, [r0, r3]
- blo 2b
- mov pc, lr
+ ARM( str r6, [r0, r3] )
+ THUMB( add r0, r0, r3 )
+#ifdef __ARMEB__
+ THUMB( mov r6, r6, ror #16 ) @ Convert word order for big-endian.
+#endif
+ THUMB( strh r6, [r0], #2 ) @ For Thumb-2, store as two halfwords
+ THUMB( mov r6, r6, lsr #16 ) @ to be robust against misaligned r3.
+ THUMB( strh r6, [r0] )
+ b 2b
ENDPROC(__fixup_smp)
1: .word .